Small gasoline engines of the type conventionally used for lawnmowers are generally equipped with a starter mechanism comprising a pull-cord attached to a recoil mechanism and to the shaft of the engine. The engine is started by the operator adjusting the carburetor setting and pulling on the cord to impart rotation to the shaft of the engine until the engine starts. This sometimes requires repetitive pulling on the cord, which is well known to be a tiresome experience.
Electric starting motors for small gasoline engines of the type conventionally used on lawnmowers are well known. The prior art electric starting motors known to applicants require extensive gearing. Additionally, a clutch is frequently employed so the starter motor may be disengaged after the gasoline engine starts. See, for example, U.S. Pat. No. 2,831,352 issued Apr. 22, 1958 to William T. Elliott et al. and U.S. Pat. No. 2,897,677 issued Aug. 4, 1959 to Samuel R. Wood.
The use of battery powered direct current starting motors for gasoline engines on lawnmowers is expensive, requiring a battery, a generator and suitable electrical and mechanical connections to render the starting motor operative.
Prior uses of electric motors operated by the alternating current available at almost all households have not heretofore provided a widely accepted starter for the gasoline engines popularly used on lawnmowers. U.S. Pat. Nos. 2,731,006; 2,804,957; 2,816,535; 2,843,101; 3,394,598; 4,365,596; and 4,372,263 all describe the use of an electric drill motor powered by the alternating current available at the household to start a gasoline engine. The various mechanisms disclosed for adapting the power of an electric drill to start a gasoline engine are economical but they have not gained wide-spread popularity, probably because of the risk of injury to the user.
U.S. Pat. No. 2,996,927 issued Aug. 22, 1961 to George W. Rome and U.S. Pat. No. 3,051,155 issued Aug. 28, 1962 to Walter L. Mehl et al. exemplify free standing installations for the starting of gasoline engines on lawnmowers by temporary engagement with an electric motor.
U.S. Pat. No. 3,500,085 issued Mar. 10, 1970 to James W. Smith illustrates the use of alternating current and a rectifier to power a direct current starter motor. It is described as being connected to a drive assembly of any of the conventional types, which would include the usual fly-wheel and clutch. The complexity of such mechanisms requires that such prior art electric starting motors be manufactured and installed as part of the original equipment, at a considerable increase in cost to the consumer as compared with gasoline engines not equipped with electric starting motors but with the familiar pull-cord starting apparatus.